Some of the linux headers were refactored recently in -CURRENT:
http://svnweb.freebsd.org/changeset/base/246085
In particular, some of the linux ioctl functions were moved to a machine-independent header. Include this header to fix the driver when built WITH_LINUX.
Fix: Patch attached with submission follows:

I have successfully tested bf's patch (from the PR) in FreeBSD/i386
environments.
First I built:
FreeBSD g1-227.catwhisker.org 10.0-CURRENT FreeBSD 10.0-CURRENT #811 r246784M/246788: Thu Feb 14 08:25:04 PST 2013 root@g1-227.catwhisker.org:/usr/obj/usr/src/sys/CANARY i386
As I rebuild the nVidia kernel module when I rebuild the kernel, the
process tested the patch. A subsequent reboot verified that I was (still)
able to use the nVidia driver in that environment.
I then booted the machine from the stable/9 slice that I had updated to:
FreeBSD g1-227.catwhisker.org 9.1-STABLE FreeBSD 9.1-STABLE #375 r246786M/246788: Thu Feb 14 04:33:20 PST 2013 root@g1-227.catwhisker.org:/usr/obj/usr/src/sys/CANARY i386
before applying the patch. I then ran:
portmaster x11/nvidia-driver
(using the patched port), then (for good measure) rebooted, and again
verified that I was able to use the nVidia driver in that environment.
Once r246085 is MFCed, the patch will need some modification as it
presently stands.
Peace,
david
--
David H. Wolfskill david@catwhisker.org
Taliban: Evil men with guns afraid of truth from a 14-year old girl.
See http://www.catwhisker.org/~david/publickey.gpg for my public key.